Metal mirror



citizen of the United States,

' .silver is also ing the mirror to maintain itsform Patented Jan. i3,1925..

EMILE J'. GUAY, 0F LYNBI, MASSACHUSETTS, ASSIGNOR TO GENERAL PANY, ACORPORATION ELECTRIC contoF NEW YORK.

ll/[ETAL MIRROR.

Application filed November 24, 1920. Serial No. 426,273. g

To all 1li/1.0m, it, 111.03/ con-cern.'

Be it known that I, EMILE J. GUAY, a residing at Lynn, county of Essex,State of Massachusetts, have invented certain new and usefulImprovements in Metal Mirrors, of which the. following is aspecification.

My invention relates to metal mirrors and the process of making them.More specifically, it relates distinguished from those mirrors in whichthe reflecting medium but which is on the backvof a glass body.

An objectof my invention is to provide an improved metal mirror, oflight weight, which is simple, efficient and rugged and which is readilymanufactured. l

Another object of my invention is to provide a novel and eicient meansof securing the reinforcing material to the mirror.

`A further object of my invention is to provide a novel method of makingsuch mirrors, particularly, the method of reinforcand preventdislocation of its focus.

My invention will bev better understood from the following descriptiontaken in mirror, as parabolic, hyperbolic or "which As the irstpstep 1nthe manufacture ofy ing my invention, view of a mirror vin the processof 1s thoroughly cleaned, andi connection with the accompanying drawingsand its` scope will be pointed/out in, the appended claims.

In the accompanying drawings illustrat- Fig. 1 is a cross-sectional formwith the first steps manufacturing my mirror indicated there0n;-Fig. 2is an elevation of a part of the perforated mat employed in my process,and Fig. 3 is a cross sectional view similar to Fig. 1 showing acompleted `mirror on I.the form.

.Referring to the drawings, the numeral 10 vindicates a mirror form. orpattern vmade preferably of plate glass, which has been molded to thedesired form and then ground' and polished on its convex surface. VThissurface, which determines p may be of `any suitable type, such spheroial, and my invention is not limited to any particular type. tration,I'have shown a parabolic mirror,

type is'more generally used.

my mirror, the convex surface of the form 'n I y is then silvered,either by achemlcal deposltor otherwise.

.lVliile in to silver metal -mirrors asl posited silver,

sired thickness.

lalloy or of nickel mat 14, preferably of soft ru the shape of theHowever, for purposes of illusf .iias filled the choring studs or pins16. rThe practice I have found silver to bethe preferred reflectingsurface, othe'r metals can be used, and While in the followingdescription I shall speak of silver as the reflecting surface,y itis tobe understood that 'anyeificiently reflecting metal could take itsplace. Also` while I have found that silver, if such is used as p bereadily deposited chemicallyit may be deposited by spraying it on theglass in a finely divided molten condition, and there are stillvotherways of depositing asuitable reflecting medium onto the glass form.Consequently, while in the following descrjption I shall mainly speak ofchemically it is tobe understood that either the silveror otherreflecting media need not be deposited chemically. l

`The deposited silver coating is preferably, althoughnot necessarily,reinforced by an electrolytic deposit of silver. silver depositv and thereinforcement are indicated by the numerals-11 and 11 respectively. Theparticular manner in which the electrolytic deposits are accomplishedforms no part of my invention. It may be done in any suitable manner,the preferred method being claimed in a pending application of CromwellA. B. Halvorson, Jr., Serial No. 364,537, filed March 9, 1920, whichapplication is assigned to theassignee of the present application.

The structure is now reinforced by an electrolytic deposit Insteacopper, I may ,produce a other of a deposit of suitable metal, lnotablycopper-nickel v alone; these and other metals would be the equivalentsof copper.l

After the'. copperv deposited onthe silver coati a perforated beryisvplaced over the copper coating. This mat may be secured to the glassform 10 in any suitable `maner, such as lby wooden clothes-pins of thespring actuated tydpe. e mat is of a desired thickness, an itsperforations 15,

Aare of suitable diameter, preferably about@ of an inch and fairly closetogether. The mirror as thus formed with `the `mat 14 curedN in themanner described is now laced in a copper-plating tank until copperperforations 15, thereb formcopper deposit 13 a gri of anelectrolytic mgon the of co per 13 of the de coating 13 has beenv the reflectingmedium, can l The loriginal deposit of` any lino action is permitted to'continue i until the copper begins to mushroom through the` per-yforations in the mat, thus forming slight eninirror 'is then The mirroris now ready for backing to .give it the necessary rigidity topieventany by the numeral 1 7, ismade of 'ment,xPortlan'd cement or plasterveo' 'ing tliin woodenwedges and the frame or by ta ping change in itsform and consequentdisplace'- ment of its focus. jTlis'backing,indicated suitable ceof Paris, or the like,` A suitable adhesivematerial may be vintiodificed between the backing 17 -Tlie cement is.appli to the co. per

pins 16 lled in, afterwhich the cement is .uniformly applied'to coverthe pins to 'a .desired thickness..

is anchored tothe copperdeposit 13 by the vpins 16, in a manner Thecement backing 17 readily understood; After vthe cement has beenpermitted 'to dry,\tlie mirror is removed from theforin 10. This may be1aceoir'iplished in one' of several- Ways.' ore'irample, b thecontraction of the the cement iny har e more or' less loosened from thelform 10 and this loosening is `promoted either byinsertbetweenthemirror the edge ofthe structure 'witha rawhi e hammer.

When tliecolper is electrolytically deposited on the s'i vercoatin tweenthe copper andthe si ver is. more than a mere adhesive contact. l. `Itis' in the nature -copper anchored to' saidl pins, ning, the mirror 1S-surface of chemically de forced by an electrolytic ,the contact be-- ofa. molecular or chemical contact. The i on the silver to be held to- Intheaccom.-

articles on the copper and iave'come so close together as gether by theatomic forces.v

.panying claims when tlieexpression molecular contact is used, a closecontact of this character is intended.

'liile I have described my invention in a specific manner, it should beunderstood that I do not limit my invention thereto, since variousmodifications skilled in the art the yspiritof my thereof .will suggestthemselves -to those without departing from invention..

'Vhat'I claim as new and desire to'secure ed by Letters Patent of theUnited States, is: -135and the, spaces between-the 1. The process' ofvproducing a mirror of the desired sha-pe which consists. in depositinga reflecting surface on-a form of highly polished glass, 'reinforcingsaid surface by an`ele`ctrolytic deposit of co' anc the surface of saidcop tlie'structure so forme 'by applying a backing of cementit'iousplastic material to the and removing the mirror from the form. 2. Amirror having an'exposed reecting ositedl silver rein- 'ckingof' copper,

per, -electrlytioring pins over A er deposit,'stiffening a grid ofanchoring lpins electrolytically formed on'said copperbackin and` abackin'e' of cement lanc iored to sai pins.

` .n witness whereof, I- )have hereunto set my hand this 20th day ofNovember, 1920. A l EMILE J. GUAY. i

